Researchers at the University of Toronto have recently found one more piece to the puzzle, and it's a worrying one. According to their study published in the Atmospheric Pollution Research journal, air pollution could be spreading up to three times farther than previously thought. This could change how we have to think about the effects of infrastructure design on public health.

Past research on air pollution from vehicle tailpipes has shown poor air quality anywhere between 100 to 250 meters (330 feet to 800 feet) of major roadways. The UT researchers have found that concentrations of pollutants from traffic are still double at a distance of 280 meters (920 feet) downwind from highway 400 north of Toronto.

One in three Canadians, and half of all Torontonians, lives within 250 metres [820 feet] of at least one major roadway. These roads, says Evans, range from 10-lane highways to most four-lane streets with steady traffic.

“We used to think that living near a major road meant that you lived near a lot of air pollution,” says Evans. “But what we’re finding is that it’s not that simple, someone living right on a major road in the suburbs may not be exposed to as much pollution as someone living downtown on a side street near many major roads.”

In the same study, Evans demonstrated that for somebody living near multiple roads, they could be exposed to up to ten times more pollutants than if they didn’t live near any major roads.

“It used to be that we measured air quality on a regional or city scale. But now we’re starting to understand that we need to measure air quality on a more micro scale, especially around major roadways," says U. of T. chemical engineer Greg Evans.

According to Health Canada, "poor air quality from traffic pollution is associated with a number of health issues, such as asthma in children and other respiratory diseases, heart disease, cancer and increased rates of premature death in adults." The Canadian Medical Association attributes 21,000 premature deaths each year (!) in Canada to air pollution.

A separate study published recently also linked traffic pollution to delayed cognitive development in children.

Clearly, something must be done to clean up our air. Walk, cycle, take transit, get a hybrid or plug-in vehicle (these have much cleaner tailpipe emissions), ask your utility about signing up for green power or go solar. All these things help.

Air pollution from cars and trucks could be spreading 3x farther than previously thought

“It used to be that we measured air quality on a regional or city scale. But now we’re starting to understand that we need to measure air quality on a more micro scale, especially around major roadways.”